Intercommunicating telephone system.



W. W. HAWKINS.

INTERGOMMUNIGATING TELEPHONE SYSTEM.

APPLICATION TILED MAY a. 1906.

964,51 3 Patented July 19, 1910.

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w. W. HAWKINS.

INTERGOMMUNIUATING TELEPHONE SYSTEM.

APPLICATION FILED MAY 9, 1906.

Patented July 19,1910.

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MNTTE WILLIAM w. HAWKINS,

0F CLEVELAND, OHIO.

INTEBCOMMUNICATING TELEPHONE SYSTEM.

To all whom it may concern:

Be it known that I, \V ILLIAM WV. HAW- lilNS, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Interconnmmieating Telephone Systems, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to an intercommunicating telephone system, in which a series of selective push buttons are employed at each telephone or station, the depression of any one of which signals the corresponding station in said system. Means are provided for holding the buttons at each station in their operated positions, and said buttons are autoi'natically released when the receiver at their station is returned to its hook. lVhile the button is locked in its operated position, the talking circuit under control of said button is closed.

In the accompanying drawings forming part of this application, Figure 1 is a plan View of the push buttons and the inclosing case therefor, said view also showing the directory plate. Fig. 2 is a bottom plan view of the supporting plate for the push buttons and contact plates, said view illus trating the detent pawls for the push buttons and the mechanism for moving said pawls to release the buttons. Fig. 3 is an enlarged transverse sectional view through the casing for the push buttons, taken substantially on line 3-3 of Fig. 1. Fig. 1 is a diagrammatic view of a series of telephone stations, showing the circuits employed in my improved system. Fig. 5 is a detail view of the receiver hook and the circuit closing device operated thereby for releasing the depressed push buttons, said view being taken substantially on the line 55 of Fig. 6. Fig. 6 is an end elevation of the struc ture shown in Fig. 5, and Fig. 7 is a detail view showing one of the selecting keys locked in depressed position, and the manually-0perated release key, said view being taken on the line 7 7 of Fig. 2.

Taking up the description of my improved system by reference to the accompanying drawings, 1 represents the casing inclosing the selecting devices, said casing having an opening 2 in its upper surface through which project the selecting or push button keys 3.

Specification of Letters Patent.

Application filed May 9, 1906.

These keys may be arranged in any con- Patented liui 19, 1910.

Serial No. 315,919.

venient manner so as to form a keyboard, but I prefer to arrange the same as shown in Fig. 1, in which they are placed in parallel rows. Any suitable number of keys, within limits, may be employed, and in Fig. 1, I have shown ten selecting keys. Arranged on the casing opposite these keys are name plates 4 forming a directory.

\Vithin the casing 1, is a main supporting plate 6, said plate resting upon legs 5 that are struck therefrom. The top plate 7 is supported from the said plate 6 by means of posts 8 extending between said plates, the plates being secured to said posts by screws, as shown. The plates 6 and 7 form guides for the keys. 7

Referring more particularly to Fig. 7, it will be seen that the upper part of each key is composed of a plug or cylinder of insulating material 9, from the lower end of which projects a' screw 10 on the lower end of which is a head 11. The keys are guided in the plate 7 by means of sleeves or bushings 12. Mounted upon the plate 6 opposite each of the keys 3, and suitably insulated from the plate 6 and from one another, are contact plates 13. One of said plates, desig nated 1 1, is longer than the remaining plates, and, as shown in Fig. 7 is bifurcated at its inner end, so as to pass on opposite sides of the lower end of the insulated part 9 of the key 3 that is appropriated thereto. The plates 13 and 1 1 are made of spring material, and the plates 1 1 serve to hold the keys 3 in their outer position. connected with the second plate 13 below the same by means of an insulating plug 15, said plug passing through the plate 13 immediately below the plate 1 1. hen one of the keys 3 is depressed, the plate 1 1 below the same will be depressed so as to bring said plate into contact with the plate 13 adjacent thereto; and the movement of the plate 14. will be transmitted through the plug 15 to the second plate 13 below, so as to establish contact between said plate 13 and the plate below the same. Motion will not be communicated to the plate 13 immediately below the plate 1 1, and the result is that when the key is thus depressed, two pairs of plates will be brought together and two contacts established. Mounted to slide for a limited distance upon the lower side of the main plate (5 is a releasing plate 16, said releasing plate being secured at one of its ends to the plate 6 by means of aheaded Each plate let is screw 17, the screw passing through an elongated slot 18 in the releasing plate. The releasing plate is normally held in a position shown in Fig. 2 by means of a coil spring 19 that is secured at one of its ends to a headed screw 20 that projects from the .the plate 6, adjacent to the armature, are

electromagnets 22, said magnets being adapted, when energized, to move the releasing plate against the tension of the spring 19. Pivoted to the underside of the plate 6 are looking detents 23, there being one of these detents for each of the buttons 3. Each of these detents is provided with a spring 24 which projects therefrom and bears against a lug 25 on the releasing plate. These springs are normally under tension, so that when a button is depressed so as to bring the head 11 below the detent, the latter will snap under the head of the button, as shown in Fig. 7, and hold the same in its operated position. Inasmuch as all of the springs 24 tend to push the releaslng plate toward the magnets 22, which tendency is resisted by the spring 19, it will be understood that the releasing plate is normally in an almost balanced condition, and the pull from the electromagnets will not be strongly resisted by the spring 19. This construction enables the magnets to exert substantially all their pull toward drawing the detent away from the head 11 of the depressed button, said detent being engaged by its lug 25 on the releasing plate. F urthermore, as the button is depressed and the detent moves under the head thereof, said detent spring relaxes its tension; and when the releasing plate is moved by the magnet, the spring 24 will exert very little pressure tending to retain the detent under the depressed button head. Mounted upon the plate 6 between the rows of buttons 3, is a ringing bar 26, the inner and downwardly turned ends of the spring plates 14 projecting over the said ringing bar and normally resting above the same. Even when the button is depressed to its locking position, as shown in Fig. 7 the end of the plate 14 is still above the ringing bar; and, in order to bring the plate and bar into contact, it is necessary to depress the button beyond its locking position. Each time the button is fully depressed, a circuit that includes the plate 14 and ringing bar, is established, and as soon as the pressure 011 the button is removed, the latter will spring back into locked position, thus breaking the ringing circuit.

As will behereinafter described, when the receiver is placed upon its hook, the electromagnets 22 will be energized, and they will then move the releasing plate 16 so as to unlock any depressed button. If, however, the operator has pushed the wrong button, it is not necessary for him to hang up his receiver in order to release the same, since I have provided a manually operated release key 27 for that purpose. This release key passes through a slot 28 in the releasing plate, the slot being in such position that when the release key is depressed a cammed portion 29 thereon engages With the releas ing plate and moves it toward the electromagnet so as to release the depressed button. The release key is normally held in its out-- ward position by a spring 30 that is coiled about the key and bears against a collar 31 on the same.

Referring now to Figs. 5 and 6, 32 is a telephone receiver hook. This hook, which may be of any preferred form, has an L- shaped arm 33 projecting from its lower side. 34 is a spring contact plate that is secured below the hook and has a curved portion 35 at its upper end in position to be engaged by the arm 33 on the receiver hook. Then the hook is depressed, as the receiver is returned to normal position thereon, the arm 33 impinges against the curved portion 35 of the contact plate, and forces it backwardly until the plate 34 makes contact with the ter minal 36, which is in the circuit with the magnets 22. The plate 34 is provided with a slot 37 in its edge, and, when the arm 33 on the hook reaches said slot, the plate 34 springs forward so as to bring the arm on the opposite side of the plate, thereby breaking the contact between said plate and the terminal 36. There is thus established a momentary contact which is sufiicient to cause the electromagnets to operate the releasing plate.

In the diagram shown in Fig. 4, the ring ing bars are shown at 26, the releasing magnets at 22, and the receiver hooks at 32. 38 is the talking battery, and 39 the ringing battery. 40 represents the receivers, and 41 the transmitters of the various telephones. 42 represents the primary of the induction coil and 43 the secondary of the said coil. 44 are the terminal bars for the telephones, and 45 are the signal bells. Each of these signal bells is normally in circuit with the long spring contact plate 14 corresponding thereto through a wire 46 which is joined to a contact plate 47 that is supported above the plate 14. There is normally an electric contact between the plate 14 and its corresponding plate 47 so that the circuit for the signal bell for that telephone is closed between these plates. the common talking wire, and 50 a common return wire. The terminal strips 44 are each provided with a series of pairs of terminals, there being as many pairs of terminals as 48 is the call wire, 49

there are stations in the system. One pair of terminals at each station is appropriated to a certain push button, and the several pairs of terminals appropriated to said button are connected together by means of the conductors 51 and 52. In the same manner the pairs of terminals in the different terminal strips that correspond with any particular push button are connected together.

From the description thus given, it will be understood that, the system being in normal condition, if station A desires to communicate with station D, A pushes his button which corresponds with Ds station. As shown in Fig. 4, this is the lower set of contacts cooperating with the ringing bars 26. The push button for D being inserted its full distance, the plate 14 makes contact with the ringing bar at station A and establishes a circuit through the following connections: Starting from the ringing battery 39, the current traverses the conductor 48, thence through the wire 53 to the bell 45 at station D. From this bell the current is conducted over wire 46 to the contact plate 47, and thence trough the plate 14 and wire 54 to the conductor 51 which con nects the pairs of terminals corresponding to station D on the various terminal strips. From the terminal strip at station D, the current proceeds through a conductor 54 to the contact strip 14 at station A which has momentarily been depressed into contact with the ringing bar 26. From this bar the current returns through the common re turn wire 50 to the battery 39. As will be seen, the releasing magnets 22 are in multiple with the signal bells; and when the current reached the conductor 55, which is connected to the call wire 48, it divided, a portion of it passing through the magnets 22, and thence through the conductors 56 to the call bell at station D. By placing the call bell and the releasing magnets in multiple or parallel, any button at station D which may have been left depressed will be released when D is called.

hen the receiver at either station A or D is restored to its hook, there is a momentary circuit established between the contact plates 34 and 36 at these stations. While thus established, a curren will flow through the releasing magnets over the following circuit: Starting from the battery 39, the current will flow through conductor 48 to the wire 55, thence through the releasing magnets 22 and the wire 57 to the contact plate 34 below the receiver hook. This plate being in contact with the terminal 36, the current will flow through said terminal 36, and wires 58 and 59 to the primary induction coil 42, and thence through the wire 60 to the common return wire 50 and thence back to the battery. Inasmuch as the primary induction coil 42 has, during the con versation, been in the circuit from the talk ing battery 38, it will be charged with current at the moment of contact between the plate 34 and terminal 36, and the electric charge which it contains will assist in building up the current through the electromagnets 22 during the momentary contact caused in their operation more than would be the case if the current therefor was not conducted through the primary induction coil, it being understood that the electromagnets and the primary induction coil are then in series in the same circuit. hen D responds to As call he pushes in his own button (D) which is the fourth button at the D station and both A and D take down their receivers, then the following circuits are established, the primary or battery circuit is as follows: battery 38, conductor 49, transmitters 41*' at both stations A and D to right hand back contact of receivers 32 through conductors 59 and primary coils 42 and conductors 60 at each of the stations A and D and over return wire 50 to battery 38.

The secondary or induced circuit is as follows: If we start at. station A the battery circuit above described will induce a current in coil 43 which will flow to the spring finger 13 below the finger 1.4 of Ds button at station A,but since 14 is depressed to contact 13, the current flows through finger 14, conductor 54, conductor 51, conductor 54 at station D, spring finger 14 of Ds button at station D, finger 13 immediately below said finger 14, thence through coil 43 at station D, through conductor 59 to left hand back contact of hook 32 at station D, through receiver 40, thence through a conductor to the bottom spring finger 13 of Ds button at station D, then through the finger 13 which is just above the bottom finger, thence through a conductor to conductor 52, thence to the spring finger 13 of Ds button at station A which is just above the bottom finger 13, thence through the bottom finger 13 and through a conductor to receiver 40, thence to left hand back contact of hook 32 at station A, through conductor 59 to coil 43 of station A which completes the circuit.

As will be seen by reference to Figs. 3 and 4, the contact plates 13 and 14 are normally separated, and are not closed except when the button corresponding thereto is depressed. At the same time, the contact 1 on plate 47 is closed against the corresponding plate 14 at all times except when the corresponding button is depressed. Consequently, when A depresses Ds button, he establishes a talking circuit through the 125 plates 13 and 14 under control of Ds button, while the talking circuit contacts corresponding' to As button remain open, and the ringing circuit contacts at As button remain closed. If, then, while A and D are 1 in conversation, another party in the system should call A, his signal bell would ring; but, being out of As talking circuit, the operation of As signal bell will not affect his telephone receiver. By this construction, the calling party does not tie up his telephone in such a way that he cannot be called during the conversation, and when called, it is only necessary for him to depress his own button in order for him to communicate with the party who has ust called him.

It will be understood from the above that when one station, as A, calls a station in the system, no other station can put itself in talking circuit with A, since it is necessary for A to depress his own button in order to establish such a talking circuit.

WVhile I have shown and described my preferred form of construction and arrange ment of circuits, variousmodifications there-- of may be resorted to without departing from the spirit of my invention, and I desire it to understood that the following claims are not intended to be restricted to the specific construction and arrangement shown any further than is made necessary by the specific terms employed therein or by the prior state of the art.

I claim:

1. In an intercommunicating telephone system, a plurality of telephone stations, a signal device for each station, a series of selective buttons for each station, means for locking any of said buttons in its operated position, and electro-magnetic means at each station for releasing the buttons at said station, said means being in circuit with the signal device for that station, whereby, when the station is signaled, any operated key at that station will be released.

2. In an intercommunicating telephone system, a plurality of telephone stations, a signal device for each station, a series of selective buttons for each station, means for locking any of said buttons in its operated position, and electro-magnetic means at each station for releasing the buttons at said station, said means being in parallel or multiple circuit with the signal device for that station, whereby, when the station is signaled, any operated key at that station will be released.

8. In an intercommunicating telephone system, a plurality of telephone stations, a signal device for each station, a series of selective buttons for each station, said buttons each having a head on its lower end, means engaging said heads for locking any I of said buttons in its operated position, a

release plate for tripping said means, and an electro-magnetic device at each station for operating the said release plate to release the buttons at said station, said electromagnetic device being in parallel circuit with the signal device for that station, whereby, when the station is signaled, any operated key at that station will be released.

4. In an intercommunicating telephone system, a plurality of telephone stations, a signal device for each station, means whereby the signal device at one station may be operated from either of the other stations in the system, a series of selective buttons at each station, contact points that are adapted to be closed by each of said buttons whereby the party called may place his telephone in a talking circuit with the party calling, the signal device of the party calling being independent of said talking circuit so that his signal device may be operated while his tele phone is in use.

5. In an intercommunicating telephone system, a plurality of telephone stations, a signal device for each station, means whereby the signal device at one station may be operated from either of the other stations in the system, a series of selective buttons at each station, means for holding the buttons in their operated positions, contact points that are adapted to be closed by each of said 1 buttons whereby the party called may maintain his telephone in a talking circuit with. the party calling, the signal device of the party calling being independent of said talking circuit so that his signal device may be operated while his telephone is in use.

6. In a selective telephone system, a plurality of normally disconnected and independent circuits, selecting devices ateach station for calling and for placing said station in circuit with any other station in the system, means for retaining said devices in their operated positions, a receiver and receiver hook for each station, electrical means controlled by the receiver hook for releas ing the selecting devices at that station, manually operative means for also releasing said selecting devices at that station, and an induction coil for said station, said induction coil comprising a primary and secondary winding, the primary winding being in circuit with the said electrical means, the said selecting devices and circuits being so related that conversations between two of the stations cannot be interrupted or interfered with by any of the other stations in the systom.

7. In a selective telephone system, a plurality of normally disconnected and independent circuits, selecting push buttons at each station for calling and for placing said station in circuit with any other station in the system, means for retaining said buttons in the operated positions, a receiver and receiver hook for each station, electrical means controlled by the receiver hook for releasing the selecting devices at the station, manually operative means for also releasing said selecting devices at that station, an induction coil for said station, said induction coil comprising a primary and secondary winding, the primary winding being in circuit with the said electrical means, the said selecting devices and circuits being so related that conversations between two of the stations cannot be interrupted or interfered with by any of the other stations in the system, and a signal device at each station, said device being in 10 multiple circuit with the said electrical means for releasing the push buttons.

In testimony whereof, I hereunto afliX my signature in the presence of two Witnesses. WILLIAM \V. HAWVKINS. Witnesses:

S. E. Fours, J. B. HULL. 

